What HS will my motor run best at?

[rebeltrousers]

I'm used to electrics, when governed the sweetspot is usually 80% throttle.

So how does that work on nitro? Genuinely have no idea, all I do currently is plug a HS number into the vbar controller and see what happens.

How do I calculate the max headspeed the motor will be capable of?
How much below this gives acceptable headroom for holding headspeed?

Of course, it's possible I'm barking up the wrong tree entirely....

[marc8090]

Very different than electric. What heli? What engine? Basically you want a headspeed that puts the engine rpms slightly above peak power.

[rebeltrousers]

Os105 on my n820.
How do I find where peak power is? Is that so a small bogging takes it into the peak rather than into the really powerless range?

[mdu6]

You should shoot to be a bit above 15,000 r.p.m. - Look at the last page of the engine manual.

Practical R.P.M = 2,000 ~16,500 r.p.m.
Power output = 3.8ps/3,75hp / 15,000 r.p.m

I believe the G4 to have a 14T pinion, so if you are using the 115T main gear - your ratio is 8,21

I would try 1850 HS x 8,21 = 15,188 engine RPM

[rebeltrousers]

Woah thanks heaps, that's exactly what I needed!
I'll post back when I've given it a go!